Method for performing beam sweeping by user equipment in wireless communication system supporting sidelink, and device therefor

ABSTRACT

Various embodiments provide a method for performing beam sweeping by a user equipment (UE) in a wireless communication system supporting a sidelink, and a device therefor. Disclosed are a method for performing beam sweeping and a device therefor, the method comprising the steps of: forming a first group for performing the beam sweeping; receiving group information related to the first group; and performing beam sweeping on the basis of the group information, wherein the group information includes area allocation information for a plurality of areas divided on the basis of the number of a plurality of beams that can be formed by UEs included in the first group, and the beam sweeping is performed only within a first area, which has been pre-configured in response to the UEs, from among the plurality of areas.

TECHNICAL FIELD

The present disclosure relates to a method for performing beam sweepingby a terminal through group-by-group cooperation in a wirelesscommunication system supporting a sidelink, and a device therefor.

BACKGROUND

Wireless communication systems have been widely deployed to providevarious types of communication services such as voice or data. Ingeneral, a wireless communication system is a multiple access systemthat supports communication of multiple users by sharing availablesystem resources (a bandwidth, transmission power, etc.). Examples ofmultiple access systems include a code division multiple access (CDMA)system, a frequency division multiple access (FDMA) system, a timedivision multiple access (TDMA) system, an orthogonal frequency divisionmultiple access (OFDMA) system, a single carrier frequency divisionmultiple access (SC-FDMA) system, and a multi carrier frequency divisionmultiple access (MC-FDMA) system.

A sidelink (SL) refers to a communication method in which a direct linkis established between user equipment (UE), and voice or data isdirectly exchanged between terminals without going through a basestation (BS). SL is being considered as one way to solve the burden ofthe base station due to the rapidly increasing data traffic.

V2X (vehicle-to-everything) refers to a communication technology thatexchanges information with other vehicles, pedestrians, andinfrastructure-built objects through wired/wireless communication. V2Xcan be divided into four types: vehicle-to-vehicle (V2V),vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), andvehicle-to-pedestrian (V2P). V2X communication may be provided through aPC5 interface and/or a Uu interface.

As more and more communication devices require larger communicationcapacities in transmitting and receiving signals, there is a need formobile broadband communication improved from the legacy radio accesstechnology. Accordingly, communication systems considering services/UEssensitive to reliability and latency are under discussion. Anext-generation radio access technology in consideration of enhancedmobile broadband communication, massive Machine Type Communication(MTC), and Ultra-Reliable and Low Latency Communication (URLLC) may bereferred to as new radio access technology (RAT) or new radio (NR). Evenin NR, vehicle-to-everything (V2X) communication may be supported.

FIG. 1 is a diagram comparing RAT-based V2X communication before NR withNR-based V2X communication.

Regarding V2X communication, in RAT prior to NR, a scheme for providinga safety service based on V2X messages such as a basic safety message(BSM), a cooperative awareness message (CAM), and a decentralizedenvironmental notification message (DENM) was mainly discussed. The V2Xmessage may include location information, dynamic information, andattribute information. For example, the UE may transmit a periodicmessage type CAM and/or an event triggered message type DENM to anotherUE.

For example, the CAM may include dynamic state information about avehicle such as direction and speed, vehicle static data such asdimensions, and basic vehicle information such as external lightingconditions and route details. For example, a UE may broadcast the CAM,and the CAM latency may be less than 100 ms. For example, when anunexpected situation such as a breakdown of the vehicle or an accidentoccurs, the UE may generate a DENM and transmit the same to another UE.For example, all vehicles within the transmission coverage of the UE mayreceive the CAM and/or DENM. In this case, the DENM may have a higherpriority than the CAM.

Regarding V2X communication, various V2X scenarios have beensubsequently introduced in NR. For example, the various V2X scenariosmay include vehicle platooning, advanced driving, extended sensors, andremote driving.

For example, based on vehicle platooning, vehicles may dynamically forma group and move together. For example, to perform platoon operationsbased on vehicle platooning, vehicles belonging to the group may receiveperiodic data from a leading vehicle. For example, the vehiclesbelonging to the group may reduce or increase the distance between thevehicles based on the periodic data.

For example, based on advanced driving, a vehicle may be semi-automatedor fully automated. For example, each vehicle may adjust trajectories ormaneuvers based on data acquired from local sensors of nearby vehiclesand/or nearby logical entities. Also, for example, each vehicle mayshare driving intention with nearby vehicles.

For example, on the basis of extended sensors, raw data or processeddata acquired through local sensors, or live video data may be exchangedbetween a vehicle, a logical entity, UEs of pedestrians and/or a V2Xapplication server. Thus, for example, the vehicle may recognize anenvironment that is improved over an environment that may be detectedusing its own sensor.

For example, for a person who cannot drive or a remote vehicle locatedin a dangerous environment, a remote driver or V2X application mayoperate or control the remote vehicle based on remote driving. Forexample, when a route is predictable as in the case of publictransportation, cloud computing-based driving may be used to operate orcontrol the remote vehicle. For example, access to a cloud-basedback-end service platform may be considered for remote driving.

A method to specify service requirements for various V2X scenarios suchas vehicle platooning, advanced driving, extended sensors, and remotedriving is being discussed in the NR-based V2X communication field.

SUMMARY

An object of various embodiments is to enable a terminal to performquick beam transmission, beam acquisition, and beam tracking byperforming cooperative beam sweeping with other terminals in a groupbased on group information or cooperation information.

It will be appreciated by those of ordinary skill in the art to whichthe embodiment(s) pertain that the objects that could be achieved withthe embodiment(s) are not limited to what has been particularlydescribed hereinabove and the above and other objects will be moreclearly understood from the following detailed description.

In one aspect of the present disclosure, provided herein is a method forperforming beam sweeping by a user equipment (UE) in a wirelesscommunication system supporting sidelink. The method may include forminga first group for performing the beam sweeping, receiving groupinformation related to the first group, and performing the beam sweepingbased on the group information, wherein the group information mayinclude region allocation information about a plurality of regionsdivided based on the number of beams formable by UEs included in thefirst group, wherein the beam sweeping may be performed only in a firstregion preconfigured to be matched with the UE among the plurality ofregions.

The group information may further include information on a groupcoefficient (G_(v)) related to the first group, wherein the groupcoefficient may be determined by ceil(M/T_(v)), wherein M may be thenumber of the plurality of regions, and T_(v) may be the number ofsynchronization signal blocks (SSBs) needed for the first group toperform the beam sweeping.

The group coefficient may correspond to the number of beamssimultaneously formable in the first group.

A product of the T_(v) and the group coefficient may be greater than alength of a symbol required to transmit a synchronization signal throughone beam.

The method may further include receiving cooperation informationincluding information on a plurality of zones divided based on alatitude and a longitude and information on a zone coefficient for eachof the plurality of zones, wherein the zone coefficient may be set to aleast value of the group coefficient for each of at least one grouplocated in a corresponding one of the zones.

The cooperation information may further include information on a timefor maintaining a reception beam for each of the plurality of zones.

A direction of the reception beam for the beam sweeping may bedetermined based on the cooperation information.

The reception beam may not be formed toward a zone having the zonecoefficient equal to 0.

The direction of the reception beam for the beam sweeping may bedetermined based on the region allocation information and thecooperation information.

A time required to maintain the direction of the reception beam may bedetermined based on the zone coefficient.

The first region may be a region corresponding to location informationabout the first UE among the plurality of regions.

A transmission beam for the beam sweeping may be formed only in adirection of a beam directed toward the first region.

In another aspect of the present disclosure, provided herein is anapparatus for performing beam sweeping in a wireless communicationsystem supporting sidelink. The apparatus may include a radio frequency(RF) transceiver, and a processor connected to the RF transceiver,wherein the processor may control the transceiver to form a first groupfor performing the beam sweeping, receive group information related tothe first group, and perform the beam sweeping based on the groupinformation, wherein the group information may include region allocationinformation about a plurality of regions divided based on the number ofbeams formable by UEs included in the first group, wherein the beamsweeping may be performed only in a first region preconfigured to bematched with the UE among the plurality of regions.

The processor may control a driving mode for the apparatus based on thegroup information.

According to various embodiments, a terminal may perform quick beamtransmission, beam acquisition, and beam tracking by performingcooperative beam sweeping with other terminals in a group based on groupinformation or cooperation information.

Effects to be achieved by embodiment(s) are not limited to what has beenparticularly described hereinabove and other effects not mentionedherein will be more clearly understood by persons skilled in the art towhich embodiment(s) pertain from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this application, illustrate embodiments of the disclosure andtogether with the description serve to explain the principle of thedisclosure.

FIG. 1 is a diagram for explaining by comparing V2X communication basedon RAT before NR and V2X communication based on NR

FIG. 2 illustrates the structure of an LTE system to which embodiment(s)are applicable.

FIG. 3 illustrates a user-plane radio protocol architecture to whichembodiment(s) are applicable.

FIG. 4 illustrates a control-plane radio protocol architecture to whichembodiment(s) are applicable.

FIG. 5 illustrates the structure of an NR system to which embodiment(s)are applicable.

FIG. 6 illustrates functional split between an NG-RAN and a 5GC to whichembodiment(s) are applicable.

FIG. 7 illustrates the structure of an NR radio frame to whichembodiment(s) are applicable.

FIG. 8 illustrates the slot structure of an NR frame to whichembodiment(s) are applicable.

FIG. 9 illustrates a radio protocol architecture for SL communication.

FIG. 10 shows the structures of an S-SSB according to CP types.

FIG. 11 illustrates UEs performing V2X or SL communication.

FIG. 12 illustrates resource units for V2X or SL communication.

FIG. 13 illustrates a procedure in which UEs perform V2X or SLcommunication according to a transmission mode.

FIG. 14 illustrates a V2X synchronization source or synchronizationreference to which embodiments(s) are applicable.

FIG. 15 illustrates a relationship between a group and a division.

FIG. 16 illustrates parameters related to beam sweeping in a specificgroup.

FIG. 17 illustrates a relationship between zone information and a zonecoefficient according to an embodiment.

FIG. 18 illustrates a beam sweep time required when cooperationinformation is not provided.

FIG. 19 illustrates a beam sweeping time based on the cooperationinformation.

FIG. 20 illustrates a method for performing beam sweeping based on groupinformation and cooperation information.

FIG. 21 illustrates a communication system applied to the presentdisclosure;

FIG. 22 illustrates wireless devices applicable to the presentdisclosure.

FIG. 23 illustrates another example of a wireless device to which thepresent disclosure is applied. The wireless device may be implemented invarious forms according to use—examples/services.

FIG. 24 illustrates a hand-held device applied to the presentdisclosure;

FIG. 25 illustrates a vehicle or an autonomous driving vehicle appliedto the present disclosure.

DETAILED DESCRIPTION

The wireless communication system is a multiple access system thatsupports communication with multiple users by sharing available systemresources (eg, bandwidth, transmission power, etc.). Examples of themultiple access system include a code division multiple access (CDMA)system, a frequency division multiple access (FDMA) system, a timedivision multiple access (TDMA) system, an orthogonal frequency divisionmultiple access (OFDMA) system, a single carrier frequency (SC-FDMA)system, a multi carrier frequency division multiple access (MC-FDMA)system, and the like.

A sidelink refers to a communication scheme in which a direct link isestablished between user equipments (UEs) to directly exchange voice ordata between UEs without assistance from a base station (BS). Thesidelink is being considered as one way to address the burden on the BScaused by rapidly increasing data traffic.

Vehicle-to-everything (V2X) refers to a communication technology forexchanging information with other vehicles, pedestrians, andinfrastructure-built objects through wired/wireless communication. V2Xmay be divided into four types: vehicle-to-vehicle (V2V),vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), andvehicle-to-pedestrian (V2P). V2X communication may be provided through aPC5 interface and/or a Uu interface.

As more and more communication devices require larger communicationcapacities in transmitting and receiving signals, there is a need formobile broadband communication improved from the legacy radio accesstechnology. Accordingly, communication systems considering services/UEssensitive to reliability and latency are under discussion. Anext-generation radio access technology in consideration of enhancedmobile broadband communication, massive MTC, and Ultra-Reliable and LowLatency Communication (URLLC) may be referred to as new radio accesstechnology (RAT) or new radio (NR). Even in NR, V2X communication may besupported.

Techniques described herein may be used in various wireless accesssystems such as code division multiple access (CDMA), frequency divisionmultiple access (FDMA), time division multiple access (TDMA), orthogonalfrequency division multiple access (OFDMA), single carrier-frequencydivision multiple access (SC-FDMA), etc. CDMA may be implemented as aradio technology such as universal terrestrial radio access (UTRA) orCDMA2000. TDMA may be implemented as a radio technology such as globalsystem for mobile communications (GSM)/general packet radio service(GPRS)/Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may beimplemented as a radio technology such as IEEE 802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE 802.20, evolved-UTRA (E-UTRA) etc. UTRA is a partof universal mobile telecommunications system (UMTS). 3GPP LTE is a partof Evolved UMTS (E-UMTS) using E-UTRA. 3GPP LTE employs OFDMA fordownlink and SC-FDMA for uplink. LTE-A is an evolution of 3GPP LTE. 3GPPNR (New Radio or New Radio Access Technology) is an evolved version of3GPP LTE/LTE-A/LTE-A pro.

5G NR is a successor technology of LTE-A, and is a new clean-slatemobile communication system with characteristics such as highperformance, low latency, and high availability. 5G NR can utilize allavailable spectrum resources, from low frequency bands below 1 GHz tointermediate frequency bands from 1 GHz to 10 GHz and high frequency(millimeter wave) bands above 24 GHz.

For clarity of explanation, LTE-A or 5G NR is mainly described, but thetechnical spirit of the embodiment(s) is not limited thereto

FIG. 2 illustrates the structure of an LTE system to which the presentdisclosure is applicable. This may also be called an evolved UMTSterrestrial radio access network (E-UTRAN) or LTE/LTE-A system.

Referring to FIG. 2, the E-UTRAN includes evolved Node Bs (eNBs) 20which provide a control plane and a user plane to UEs 10. A UE 10 may befixed or mobile, and may also be referred to as a mobile station (MS),user terminal (UT), subscriber station (SS), mobile terminal (MT), orwireless device. An eNB 20 is a fixed station communication with the UE10 and may also be referred to as a base station (BS), a basetransceiver system (BTS), or an access point.

eNBs 20 may be connected to each other via an X2 interface. An eNB 20 isconnected to an evolved packet core (EPC) 39 via an S1 interface. Morespecifically, the eNB 20 is connected to a mobility management entity(MME) via an S1-MME interface and to a serving gateway (S-GW) via anS1-U interface.

The EPC 30 includes an MME, an S-GW, and a packet data network-gateway(P-GW). The MME has access information or capability information aboutUEs, which are mainly used for mobility management of the UEs. The S-GWis a gateway having the E-UTRAN as an end point, and the P-GW is agateway having a packet data network (PDN) as an end point.

Based on the lowest three layers of the open system interconnection(OSI) reference model known in communication systems, the radio protocolstack between a UE and a network may be divided into Layer 1 (L1), Layer2 (L2) and Layer 3 (L3). These layers are defined in pairs between a UEand an Evolved UTRAN (E-UTRAN), for data transmission via the Uuinterface. The physical (PHY) layer at L1 provides an informationtransfer service on physical channels. The radio resource control (RRC)layer at L3 functions to control radio resources between the UE and thenetwork. For this purpose, the RRC layer exchanges RRC messages betweenthe UE and an eNB.

FIG. 3 illustrates a user-plane radio protocol architecture to which thepresent disclosure is applicable.

FIG. 4 illustrates a control-plane radio protocol architecture to whichthe present disclosure is applicable. A user plane is a protocol stackfor user data transmission, and a control plane is a protocol stack forcontrol signal transmission.

Referring to FIGS. 3 and 4, the PHY layer provides an informationtransfer service to its higher layer on physical channels. The PHY layeris connected to the medium access control (MAC) layer through transportchannels and data is transferred between the MAC layer and the PHY layeron the transport channels. The transport channels are divided accordingto features with which data is transmitted via a radio interface.

Data is transmitted on physical channels between different PHY layers,that is, the PHY layers of a transmitter and a receiver. The physicalchannels may be modulated in orthogonal frequency division multiplexing(OFDM) and use time and frequencies as radio resources.

The MAC layer provides services to a higher layer, radio link control(RLC) on logical channels. The MAC layer provides a function of mappingfrom a plurality of logical channels to a plurality of transportchannels. Further, the MAC layer provides a logical channel multiplexingfunction by mapping a plurality of logical channels to a singletransport channel. A MAC sublayer provides a data transmission serviceon the logical channels.

The RLC layer performs concatenation, segmentation, and reassembly forRLC serving data units (SDUs). In order to guarantee various quality ofservice (QoS) requirements of each radio bearer (RB), the RLC layerprovides three operation modes, transparent mode (TM), unacknowledgedmode (UM), and acknowledged Mode (AM). An AM RLC provides errorcorrection through automatic repeat request (ARQ).

The RRC layer is defined only in the control plane and controls logicalchannels, transport channels, and physical channels in relation toconfiguration, reconfiguration, and release of RBs. An RB refers to alogical path provided by L1 (the PHY layer) and L2 (the MAC layer, theRLC layer, and the packet data convergence protocol (PDCP) layer), fordata transmission between the UE and the network.

The user-plane functions of the PDCP layer include user datatransmission, header compression, and ciphering. The control-planefunctions of the PDCP layer include control-plane data transmission andciphering/integrity protection.

RB establishment amounts to a process of defining radio protocol layersand channel features and configuring specific parameters and operationmethods in order to provide a specific service. RBs may be classifiedinto two types, signaling radio bearer (SRB) and data radio bearer(DRB). The SRB is used as a path in which an RRC message is transmittedon the control plane, whereas the DRB is used as a path in which userdata is transmitted on the user plane.

Once an RRC connection is established between the RRC layer of the UEand the RRC layer of the E-UTRAN, the UE is placed in RRC_CONNECTEDstate, and otherwise, the UE is placed in RRC_IDLE state. In NR,RRC_INACTIVE state is additionally defined. A UE in the RRC_INACTIVEstate may maintain a connection to a core network, while releasing aconnection from an eNB.

DL transport channels carrying data from the network to the UE include abroadcast channel (BCH) on which system information is transmitted and aDL shared channel (DL SCH) on which user traffic or a control message istransmitted. Traffic or a control message of a DL multicast or broadcastservice may be transmitted on the DL-SCH or a DL multicast channel (DLMCH). UL transport channels carrying data from the UE to the networkinclude a random access channel (RACH) on which an initial controlmessage is transmitted and an UL shared channel (UL SCH) on which usertraffic or a control message is transmitted.

The logical channels which are above and mapped to the transportchannels include a broadcast control channel (BCCH), a paging controlchannel (PCCH), a common control channel (CCCH), a multicast controlchannel (MCCH), and a multicast traffic channel (MTCH).

A physical channel includes a plurality of OFDM symbols in the timedomain by a plurality of subcarriers in the frequency domain. Onesubframe includes a plurality of OFDM symbols in the time domain. An RBis a resource allocation unit defined by a plurality of OFDM symbols bya plurality of subcarriers. Further, each subframe may use specificsubcarriers of specific OFDM symbols (e.g., the first OFDM symbol) in acorresponding subframe for a physical DL control channel (PDCCH), thatis, an L1/L2 control channel. A transmission time interval (TTI) is aunit time for subframe transmission.

FIG. 5 illustrates the structure of a NR system to which the presentdisclosure is applicable.

Referring to FIG. 5, a next generation radio access network (NG-RAN) mayinclude a next generation Node B (gNB) and/or an eNB, which providesuser-plane and control-plane protocol termination to a UE. In FIG. 5,the NG-RAN is shown as including only gNBs, by way of example. A gNB andan eNB are connected to each other via an Xn interface. The gNB and theeNB are connected to a 5G core network (5GC) via an NG interface. Morespecifically, the gNB and the eNB are connected to an access andmobility management function (AMF) via an NG-C interface and to a userplane function (UPF) via an NG-U interface.

FIG. 6 illustrates functional split between the NG-RAN and the 5GC towhich the present disclosure is applicable.

Referring to FIG. 6, a gNB may provide functions including inter-cellradio resource management (RRM), radio admission control, measurementconfiguration and provision, and dynamic resource allocation. The AMFmay provide functions such as non-access stratum (NAS) security andidle-state mobility processing. The UPF may provide functions includingmobility anchoring and protocol data unit (PDU) processing. A sessionmanagement function (SMF) may provide functions including UE Internetprotocol (IP) address allocation and PDU session control.

FIG. 7 illustrates the structure of a NR radio frame to which thepresent disclosure is applicable.

Referring to FIG. 7, a radio frame may be used for UL transmission andDL transmission in NR. A radio frame is 10 ms in length, and may bedefined by two 5-ms half-frames. An HF may include five 1-ms subframes.A subframe may be divided into one or more slots, and the number ofslots in an SF may be determined according to a subcarrier spacing(SCS). Each slot may include 12 or 14 OFDM(A) symbols according to acyclic prefix (CP).

In a normal CP (NCP) case, each slot may include 14 symbols, whereas inan extended CP (ECP) case, each slot may include 12 symbols. Herein, asymbol may be an OFDM symbol (or CP-OFDM symbol) or an SC-FDMA symbol(or DFT-s-OFDM symbol).

Table 1 below lists the number of symbols per slot N^(slot) _(symb), thenumber of slots per frame N^(frame,u) _(slot), and the number of slotsper subframe N^(subframe,u) _(slot) according to an SCS configuration μin the NCP case.

TABLE 1 SCS (15 * 2u) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 15 KHz (u = 0) 14 10 1 30 KHz (u = 1) 14 20 2 60KHz (u = 2) 14 40 4 120 KHz (u = 3)  14 80 8 240 KHz (u = 4)  14 160 16

Table 2 below lists the number of symbols per slot, the number of slotsper frame, and the number of slots per subframe according to an SCS inthe ECP case.

TABLE 2 SCS (15 * 2{circumflex over ( )}u) N^(slot) _(symb) N^(frame,u)_(slot) N^(subframe,u) _(slot) 60 KHz (u = 2) 12 40 4

In the NR system, different OFDM(A) numerologies (e.g., SCSs, CPlengths, etc.) may be configured for a plurality of cells aggregated forone UE. Thus, the (absolute) duration of a time resource (e.g., SF,slot, or TTI) including the same number of symbols may differ betweenthe aggregated cells (such a time resource is commonly referred to as atime unit (TU) for convenience of description).

In NR, multiple numerologies or SCSs to support various 5G services maybe supported. For example, a wide area in conventional cellular bandsmay be supported when the SCS is 15 kHz, and a dense urban environment,lower latency, and a wider carrier bandwidth may be supported when theSCS is 30 kHz/60 kHz. When the SCS is 60 kHz or higher, a bandwidthwider than 24.25 GHz may be supported to overcome phase noise.

The NR frequency band may be defined as two types of frequency ranges.The two types of frequency ranges may be FR1 and FR2. The numericalvalues of the frequency ranges may be changed. For example, the twotypes of frequency ranges may be configured as shown in Table 3 below.Among the frequency ranges used in the NR system, FR1 may represent “sub6 GHz range” and FR2 may represent “above 6 GHz range” and may be calledmillimeter wave (mmW).

TABLE 3 Frequency Range Corresponding Subcarrier designation frequencyrange Spacing (SCS) FR1  450 MHz-6000 MHz  15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

As mentioned above, the numerical values of the frequency ranges of theNR system may be changed. For example, FR1 may include a band of 410 MHzto 7125 MHz as shown in Table 4 below. That is, FR1 may include afrequency band of 6 GHz (or 5850 MHz, 5900 MHz, 5925 MHz, etc.) orhigher. For example, the frequency band of 6 GHz (or 5850 MHz, 5900 MHz,5925 MHz, etc.) or higher included in FR1 may include an unlicensedband. The unlicensed band may be used for various purposes, for example,for communication for vehicles (e.g., autonomous driving).

TABLE 4 Frequency Range Corresponding Subcarrier designation frequencyrange Spacing (SCS) FR1  410 MHz-7125 MHz  15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

FIG. 8 illustrates the slot structure of a NR frame to which the presentdisclosure is applicable.

Referring to FIG. 8, one slot includes a plurality of symbols in thetime domain. For example, one slot may include 14 symbols in a normal CPand 12 symbols in an extended CP. Alternatively, one slot may include 7symbols in the normal CP and 6 symbols in the extended CP.

A carrier may include a plurality of subcarriers in the frequencydomain. A resource block (RB) is defined as a plurality of consecutivesubcarriers (e.g., 12 subcarriers) in the frequency domain. A bandwidthpart (BWP) may be defined as a plurality of consecutive (P)RBs in thefrequency domain, and the BWP may correspond to one numerology (e.g.,SCS, CP length, etc.). The carrier may include up to N (e.g., 5) BWPs.Data communication may be conducted in an activated BWP. In a resourcegrid, each element.

The wireless interface between UEs or the wireless interface between aUE and a network may be composed of an L1 layer, an L2 layer, and an L3layer. In various embodiments of the present disclosure, the L1 layermay represent a physical layer. The L2 layer may represent, for example,at least one of a MAC layer, an RLC layer, a PDCP layer, and an SDAPlayer. The L3 layer may represent, for example, an RRC layer.

Hereinafter, V2X or sidelink (SL) communication will be described.

FIG. 9 illustrates a radio protocol architecture for SL communication.Specifically, FIG. 9-(a) shows a user plane protocol stack of NR, andFIG. 9-(b) shows a control plane protocol stack of NR.

Hereinafter, a sidelink synchronization signal (SLSS) andsynchronization information will be described.

The SLSS is an SL-specific sequence, and may include a primary sidelinksynchronization signal (PSSS) and a secondary sidelink synchronizationsignal (SSSS). The PSSS may be referred to as a sidelink primarysynchronization signal (S-PSS), and the S-SSS may be referred to as asidelink secondary synchronization signal (S-SSS). For example,length-127 M-sequences may be used for the S-PSS, and length-127 goldsequences may be used for the S-SSS. For example, the UE may detect aninitial signal and acquire synchronization using the S-PSS. For example,the UE may acquire detailed synchronization using the S-PSS and theS-SSS, and may detect a synchronization signal ID.

A physical sidelink broadcast channel (PSBCH) may be a (broadcast)channel on which basic (system) information that the UE needs to knowfirst before transmission and reception of an SL signal is transmitted.For example, the basic information may include SLSS related information,a duplex mode (DM), time division duplex uplink/downlink (TDD UL/DL)configuration, resource pool related information, the type of anapplication related to the SLSS, a subframe offset, and broadcastinformation. For example, for evaluation of PSBCH performance, thepayload size of PSBCH in NR V2X may be 56 bits including CRC of 24 bits.

The S-PSS, S-SSS, and PSBCH may be included in a block format (e.g., anSL synchronization signal (SS)/PSBCH block, hereinaftersidelink-synchronization signal block (S-SSB)) supporting periodictransmission. The S-SSB may have the same numerology (i.e., SCS and CPlength) as a physical sidelink control channel (PSCCH)/physical sidelinkshared channel (PSSCH) in the carrier, and the transmission bandwidththereof may be within a (pre)set sidelink BWP (SL BWP). For example, thebandwidth of the S-SSB may be 11 resource blocks (RBs). For example, thePSBCH may span 11 RBs. The frequency position of the S-SSB may be(pre)set. Accordingly, the UE does not need to perform hypothesisdetection at a frequency to discover the S-SSB in the carrier.

In the NR SL system, a plurality of numerologies having different SCSsand/or CP lengths may be supported. In this case, as the SCS increases,the length of the time resource in which the transmitting UE transmitsthe S-SSB may be shortened. Thereby, the coverage of the S-SSB may benarrowed. Accordingly, in order to guarantee the coverage of the S-SSB,the transmitting UE may transmit one or more S-SSBs to the receiving UEwithin one S-SSB transmission period according to the SCS. For example,the number of S-SSBs that the transmitting UE transmits to the receivingUE within one S-SSB transmission period may be pre-configured orconfigured for the transmitting UE. For example, the S-SSB transmissionperiod may be 160 ms. For example, for all SCSs, the S-SSB transmissionperiod of 160 ms may be supported.

For example, when the SCS is 15 kHz in FR1, the transmitting UE maytransmit one or two S-SSBs to the receiving UE within one S-SSBtransmission period. For example, when the SCS is 30 kHz in FR1, thetransmitting UE may transmit one or two S-SSBs to the receiving UEwithin one S-SSB transmission period. For example, when the SCS is 60kHz in FR1, the transmitting UE may transmit one, two, or four S-SSBs tothe receiving UE within one S-SSB transmission period.

For example, when the SCS is 60 kHz in FR2, the transmitting UE maytransmit 1, 2, 4, 8, 16 or 32 S-SSBs to the receiving UE within oneS-SSB transmission period. For example, when SCS is 120 kHz in FR2, thetransmitting UE may transmit 1, 2, 4, 8, 16, 32 or 64 S-SSBs to thereceiving UE within one S-SSB transmission period.

When the SCS is 60 kHz, two types of CPs may be supported. In addition,the structure of the S-SSB transmitted from the transmitting UE to thereceiving UE may depend on the CP type. For example, the CP type may benormal CP (NCP) or extended CP (ECP). Specifically, for example, whenthe CP type is NCP, the number of symbols to which the PSBCH is mappedin the S-SSB transmitted by the transmitting UE may be 9 or 8. On theother hand, for example, when the CP type is ECP, the number of symbolsto which the PSBCH is mapped in the S-SSB transmitted by thetransmitting UE may be 7 or 6. For example, the PSBCH may be mapped tothe first symbol in the S-SSB transmitted by the transmitting UE. Forexample, upon receiving the S-SSB, the receiving UE may perform anautomatic gain control (AGC) operation in the period of the first symbolfor the S-SSB.

FIG. 10 illustrates the structures of an S-SSB according to CP types.FIG. 10-(a) shows the structure of the S-SSB when the CP type is NCP.

For example, the structure of the S-SSB, that is, the order of symbolsto which the S-PSS, S-SSS, and PSBCH are mapped in the S-SSB transmittedby the transmitting UE when the CP type is NCP may be shown in FIG. 20.

FIG. 10-(b) shows the structure of the S-SSB when the CP type is ECP.

For example, when the CP type is ECP, the number of symbols to which thetransmitting UE maps the PSBCH after the S-SSS in the S-SSB may be 6,unlike in FIG. 20. Accordingly, the coverage of the S-SSB may differbetween the CP types, NCP and ECP.

Each SLSS may have an SL synchronization identifier (SLSS ID).

For example, in the case of LTE SL or LTE V2X, the value of the SLSS IDmay be defined based on a combination of two different S-PSS sequencesand 168 different S-SSS sequences. For example, the number of SLSS IDsmay be 336. For example, the value of the SLSS ID may be any one of 0 to335.

For example, in the case of NR SL or NR V2X, the value of the SLSS IDmay be defined based on a combination of two different S-PSS sequencesand 336 different S-SSS sequences. For example, the number of SLSS IDsmay be 672. For example, the value of the SLSS ID may be any one of 0 to671. For example, one S-PSS of the two different S-PSSs may beassociated with in-coverage, and the other S-PSS may be associated without-of-coverage. For example, SLSS IDs of 0 to 335 may be used inin-coverage, and SLSS IDs of 336 to 671 may be used in out-of-coverage.

In order to improve the S-SSB reception performance of the receiving UE,the transmitting UE needs to optimize the transmit power according tothe characteristics of respective signals constituting the S-SSB. Forexample, according to the peak to average power ratio (PAPR) of eachsignal constituting the S-SSB, the transmitting UE may determine thevalue of maximum power reduction (MPR) for each signal. For example,when the PAPR differs between the S-PSS and the S-SSS which constitutethe S-SSB, the transmitting UE may apply an optimal MPR value totransmission of each of the S-PSS and the S-SSS in order to improve theS-SSB reception performance of the receiving UE. Also, for example, inorder for the transmitting UE to perform an amplification operation oneach signal, a transition period may be applied. The transition periodmay reserve a time required for the transmitter amplifier of thetransmitting UE to perform a normal operation at the boundary where thetransmit power of the transmitting UE varies. For example, in the caseof FR1, the transition period may be 10 μs. For example, in the case ofFR2, the transition period may be 5 μs. For example, a search window inwhich the receiving UE is to detect the S-PSS may be 80 ms and/or 160ms.

FIG. 11 illustrates UEs performing V2X or SL communication.

Referring to FIG. 11, in V2X or SL communication, the term UE may mainlyrefer to a user's UE. However, when network equipment such as a BStransmits and receives signals according to a communication schemebetween UEs, the BS may also be regarded as a kind of UE. For example,UE 1 may be the first device 100, and UE 2 may be the second device 200.

For example, UE 1 may select a resource unit corresponding to a specificresource in a resource pool, which represents a set of resources. Then,UE 1 may transmit an SL signal through the resource unit. For example,UE 2, which is a receiving UE, may receive a configuration of a resourcepool in which UE 1 may transmit a signal, and may detect a signal of UE1 in the resource pool.

Here, when UE 1 is within the connection range of the BS, the BS mayinform UE 1 of a resource pool. On the other hand, when the UE 1 isoutside the connection range of the BS, another UE may inform UE 1 ofthe resource pool, or UE 1 may use a preconfigured resource pool.

In general, the resource pool may be composed of a plurality of resourceunits, and each UE may select one or multiple resource units andtransmit an SL signal through the selected units.

FIG. 12 illustrates resource units for V2X or SL communication.

Referring to FIG. 12, the frequency resources of a resource pool may bedivided into N_(F) sets, and the time resources of the resource pool maybe divided into N_(T) sets. Accordingly, a total of N_(F)*N_(T) resourceunits may be defined in the resource pool. FIG. 12 shows an exemplarycase where the resource pool is repeated with a periodicity of NTsubframes.

As shown in FIG. 12, one resource unit (e.g., Unit #0) may appearperiodically and repeatedly. Alternatively, in order to obtain adiversity effect in the time or frequency dimension, an index of aphysical resource unit to which one logical resource unit is mapped maychange in a predetermined pattern over time. In this structure ofresource units, the resource pool may represent a set of resource unitsavailable to a UE which intends to transmit an SL signal.

Resource pools may be subdivided into several types. For example,according to the content in the SL signal transmitted in each resourcepool, the resource pools may be divided as follows.

(1) Scheduling assignment (SA) may be a signal including informationsuch as a position of a resource through which a transmitting UEtransmits an SL data channel, a modulation and coding scheme (MCS) ormultiple input multiple output (MIMO) transmission scheme required fordemodulation of other data channels, and timing advance (TA). The SA maybe multiplexed with SL data and transmitted through the same resourceunit. In this case, an SA resource pool may represent a resource pool inwhich SA is multiplexed with SL data and transmitted. The SA may bereferred to as an SL control channel.

(2) SL data channel (physical sidelink shared channel (PSSCH)) may be aresource pool through which the transmitting UE transmits user data.When the SA and SL data are multiplexed and transmitted together in thesame resource unit, only the SL data channel except for the SAinformation may be transmitted in the resource pool for the SL datachannel. In other words, resource elements (REs) used to transmit the SAinformation in individual resource units in the SA resource pool maystill be used to transmit the SL data in the resource pool of the SLdata channel. For example, the transmitting UE may map the PSSCH toconsecutive PRBs and transmit the same.

(3) The discovery channel may be a resource pool used for thetransmitting UE to transmit information such as the ID thereof. Throughthis channel, the transmitting UE may allow a neighboring UE to discoverthe transmitting UE.

Even when the SL signals described above have the same content, they mayuse different resource pools according to the transmission/receptionproperties of the SL signals. For example, even when the SL data channelor discovery message is the same among the signals, it may be classifiedinto different resource pools according to determination of the SLsignal transmission timing (e.g., transmission at the reception time ofthe synchronization reference signal or transmission by applying apredetermined TA at the reception time), a resource allocation scheme(e.g., the BS designates individual signal transmission resources toindividual transmitting UEs or individual transmission UEs selectindividual signal transmission resources within the resource pool),signal format (e.g., the number of symbols occupied by each SL signal ina subframe, or the number of subframes used for transmission of one SLsignal), signal strength from a BS, the strength of transmit power of anSL UE, and the like.

Hereinafter, resource allocation in the SL will be described.

FIG. 13 illustrates a procedure in which UEs perform V2X or SLcommunication according to a transmission mode. In various embodimentsof the present disclosure, the transmission mode may be referred to as amode or a resource allocation mode. Hereinafter, for simplicity, thetransmission mode in LTE may be referred to as an LTE transmission mode,and the transmission mode in NR may be referred to as an NR resourceallocation mode.

For example, FIG. 13-(a) illustrates a UE operation related to LTEtransmission mode 1 or LTE transmission mode 3. Alternatively, forexample, FIG. 24-(a) illustrates a UE operation related to NR resourceallocation mode 1. For example, LTE transmission mode 1 may be appliedto general SL communication, and LTE transmission mode 3 may be appliedto V2X communication.

For example, FIG. 13-(b) illustrates a UE operation related to LTEtransmission mode 2 or LTE transmission mode 4. Alternatively, forexample, FIG. 24-(b) illustrates a UE operation related to NR resourceallocation mode 2.

Referring to FIG. 13-(a), in LTE transmission mode 1, LTE transmissionmode 3 or NR resource allocation mode 1, the BS may schedule an SLresource to be used by the UE for SL transmission. For example, the BSmay perform resource scheduling for UE 1 through PDCCH (morespecifically, downlink control information (DCI)), and UE 1 may performV2X or SL communication with UE 2 according to the resource scheduling.For example, UE 1 may transmit sidelink control information (SCI) to UE2 on a physical sidelink control channel (PSCCH), and then transmit datawhich is based on the SCI to UE 2 on a physical sidelink shared channel(PSSCH).

For example, in NR resource allocation mode 1, the UE may be providedwith or allocated resources for one or more SL transmissions of atransport block (TB) from the BS through a dynamic grant. For example,the BS may provide a resource for transmission of the PSCCH and/or PSSCHto the UE using the dynamic grant. For example, the transmitting UE mayreport the SL hybrid automatic repeat request (HARQ) feedback receivedfrom the receiving UE to the BS. In this case, the PUCCH resource andtiming for reporting the SL HARQ feedback to the BS may be determinedbased on an indication in the PDCCH through the BS is to allocate aresource for SL transmission.

For example, DCI may represent a slot offset between DCI reception and afirst SL transmission scheduled by DCI. For example, the minimum gapbetween the DCI scheduling a SL transmission resource and the firstscheduled SL transmission resource may not be shorter than theprocessing time of the corresponding UE.

For example, in NR resource allocation mode 1, the UE may beperiodically provided with or allocated a resource set from the BS for aplurality of SL transmissions through a configured grant. For example,the configured grant may include configured grant type 1 or configuredgrant type 2. For example, the UE may determine a TB to be transmittedin each occasion indicated by a given configured grant.

For example, the BS may allocate SL resources to the UE on the samecarrier, and may allocate SL resources to the UE on different carriers.

For example, an NR BS may control LTE-based SL communication. Forexample, the NR BS may transmit NR DCI to the UE to schedule an LTE SLresource. In this case, for example, a new RNTI for scrambling the NRDCI may be defined. For example, the UE may include an NR SL module andan LTE SL module.

For example, after the UE including the NR SL module and the LTE SLmodule receives NR SL DCI from the gNB, the NR SL module may transformthe NR SL DCI to LTE DCI type 5A, and the NR SL module may deliver LTEDCI type 5A to the LTE SL module in units of X ms. For example, the LTESL module may apply activation and/or release to the first LTE subframeZ ms after the LTE SL module receives LTE DCI format 5A from the NR SLmodule. For example, the X may be dynamically indicated using a field ofDCI. For example, the minimum value of X may depend on the UEcapability. For example, the UE may report a single value according tothe UE capability. For example, X may be a positive number.

Referring to FIG. 13-(b), in LTE transmission mode 2, LTE transmissionmode 4, or NR resource allocation mode 2, the UE may determine AN SLresource within the SL resources configured by the BS/network or thepreconfigured SL resources. For example, the configured SL resources orthe preconfigured SL resources may be a resource pool. For example, theUE may autonomously select or schedule a resource for SL transmission.For example, the UE may autonomously select a resource within theconfigured resource pool to perform SL communication. For example, theUE may select a resource within a selection window by performing asensing and resource (re)selection procedure. For example, the sensingmay be performed on a per sub-channel basis. In addition, UE 1, whichhas selected a resource within the resource pool, may transmit SCI to UE2 through the PSCCH, and then transmit data, which is based on the SCI,to UE 2 through the PSSCH.

For example, a UE may assist in selecting an SL resource for another UE.For example, in NR resource allocation mode 2, the UE may receive aconfigured grant for SL transmission. For example, in NR resourceallocation mode 2, the UE may schedule SL transmission of another UE.For example, in NR resource allocation mode 2, the UE may reserve an SLresource for blind retransmission.

For example, in NR resource allocation mode 2, UE 1 may indicate thepriority of SL transmission to UE 2 using the SCI. For example, UE 2 maydecode the SCI. UE 2 may perform sensing and/or resource (re)selectionbased on the priority. For example, the resource (re)selection proceduremay include an operation of identifying candidate resources in aresource selection window by UE 2, and an operation of selecting, by UE2, a resource for (re)transmission from among the identified candidateresources. For example, the resource selection window may be a timeinterval during which the UE selects the resource for SL transmission.For example, after UE 2 triggers resource (re)selection, the resourceselection window may start at T1≥0. The resource selection window may belimited by the remaining packet delay budget of UE 2. For example, inthe operation of identifying the candidate resources in the resourceselection window by UE 2, a specific resource may be indicated by theSCI received by UE 2 from UE 1. When the L1 SL RSRP measurement valuefor the specific resource exceeds an SL RSRP threshold, UE 2 may notdetermine the specific resource as a candidate resource. For example,the SL RSRP threshold may be determined based on the priority of the SLtransmission indicated by the SCI received by UE 2 from UE 1 and thepriority of the SL transmission on the resource selected by UE 2.

For example, the L1 SL RSRP may be measured based on an SL demodulationreference signal (DMRS). For example, one or more PSSCH DMRS patternsmay be configured or preconfigured for each resource pool in the timedomain. For example, PDSCH DMRS configuration type 1 and/or type 2 maybe the same as or similar to the frequency domain pattern of the PSSCHDMRS. For example, the exact DMRS pattern may be indicated by the SCI.For example, in NR resource allocation mode 2, the transmitting UE mayselect a specific DMRS pattern from among DMRS patterns configured orpreconfigured for the resource pool.

For example, in NR resource allocation mode 2, based on the sensing andresource (re)selection procedure, the transmitting UE may performinitial transmission of a TB without reservation. For example, based onthe sensing and resource (re)selection procedure, using the SCIassociated with a first TB, the transmitting UE may reserve the SLresource for initial transmission of a second TB.

For example, in NR resource allocation mode 2, the UE may reserve aresource for feedback-based PSSCH retransmission through signalingrelated to previous transmission of the same TB. For example, themaximum number of SL resources reserved by one transmission includingthe current transmission may be 2, 3, or 4. For example, the maximumnumber of SL resources may be the same regardless of whether HARQfeedback is enabled. For example, the maximum number of HARQ(re)transmissions for one TB may be limited by configuration orpre-configuration. For example, the maximum number of HARQ(re)transmissions may be up to 32. For example, when the configurationor pre-configuration is not present, the maximum number of HARQ(re)transmissions may be unspecified. For example, the configuration orpre-configuration may be for the transmitting UE. For example, in NRresource allocation mode 2, HARQ feedback for releasing resources notused by the UE may be supported.

For example, in NR resource allocation mode 2, the UE may indicate toanother UE one or more sub-channels and/or slots used by the UE, usingthe SCI. For example, the UE may indicate to another UE one or moresub-channels and/or slots reserved by the UE for PSSCH (re)transmission,using SCI. For example, the minimum allocation unit of the SL resourcemay be a slot. For example, the size of the sub-channel may beconfigured for the UE or may be preconfigured.

Hereinafter, sidelink control information (SCI) will be described.

Control information transmitted by the BS to the UE on the PDCCH may bereferred to as downlink control information (DCI), whereas controlinformation transmitted by the UE to another UE on the PSCCH may bereferred to as SCI. For example, before decoding the PSCCH, the UE maybe aware of the start symbol of the PSCCH and/or the number of symbolsof the PSCCH. For example, the SCI may include SL schedulinginformation. For example, the UE may transmit at least one SCI toanother UE to schedule the PSSCH. For example, one or more SCI formatsmay be defined.

For example, the transmitting UE may transmit the SCI to the receivingUE on the PSCCH. The receiving UE may decode one SCI to receive thePSSCH from the transmitting UE.

For example, the transmitting UE may transmit two consecutive SCIs(e.g., 2-stage SCI) to the receiving UE on the PSCCH and/or the PSSCH.The receiving UE may decode the two consecutive SCIs (e.g., 2-stage SCI)to receive the PSSCH from the transmitting UE. For example, when the SCIconfiguration fields are divided into two groups in consideration of the(relatively) high SCI payload size, the SCI including a first SCIconfiguration field group may be referred to as first SCI or 1st SCI,and the SCI including a second SCI configuration field group may bereferred to as second SCI or 2nd SCI. For example, the transmitting UEmay transmit the first SCI to the receiving UE on the PSCCH. Forexample, the transmitting UE may transmit the second SCI to thereceiving UE on the PSCCH and/or the PSSCH. For example, the second SCImay be transmitted to the receiving UE on the (independent) PSCCH, ormay be piggybacked together with data and transmitted on the PSSCH. Forexample, the two consecutive SCIs may be applied for differenttransmissions (e.g., unicast, broadcast, or groupcast).

For example, the transmitting UE may transmit some or all of thefollowing information to the receiving UE through SCI. Here, forexample, the transmitting UE may transmit some or all of the followinginformation to the receiving UE through the first SCI and/or the secondSCI:

-   -   PSSCH and/or PSCCH related resource allocation information, for        example, the positions/number of time/frequency resources,        resource reservation information (e.g., periodicity); and/or    -   SL CSI report request indicator or SL (L1) RSRP (and/or SL (L1)        RSRQ and/or SL (L1) RSSI) report request indicator; and/or    -   SL CSI transmission indicator (or SL (L1) RSRP (and/or SL (L1)        RSRQ and/or SL (L1) RSSI) information transmission indicator)        (on PSSCH); and/or    -   MCS information; and/or    -   transmit power information; and/or    -   L1 destination ID information and/or L1 source ID information;        and/or    -   SL HARQ process ID information; and/or    -   new data indicator (NDI) information; and/or    -   redundancy version (RV) information; and/or    -   (transmission traffic/packet related) QoS information; e.g.,        priority information; and/or    -   SL CSI-RS transmission indicator or information on the number of        (transmitted) SL CSI-RS antenna ports;    -   Location information about the transmitting UE or location (or        distance/area) information about a target receiving UE (to which        a request for SL HARQ feedback is made); and/or    -   information about a reference signal (e.g., DMRS, etc.) related        to decoding and/or channel estimation of data transmitted on the        PSSCH, for example, information related to a pattern of a        (time-frequency) mapping resource of DMRS, rank information,        antenna port index information.

For example, the first SCI may include information related to channelsensing. For example, the receiving UE may decode the second SCI usingthe PSSCH DMRS. A polar code used for the PDCCH may be applied to thesecond SCI. For example, in the resource pool, the payload size of thefirst SCI may be the same for unicast, groupcast and broadcast. Afterdecoding the first SCI, the receiving UE does not need to perform blinddecoding of the second SCI. For example, the first SCI may includescheduling information about the second SCI.

In various embodiments of the present disclosure, since the transmittingUE may transmit at least one of SCI, the first SCI, and/or the secondSCI to the receiving UE on the PSCCH, the PSCCH may bereplaced/substituted with at least one of the SCI, the first SCI, and/orthe second SCI. Additionally/alternatively, for example, the SCI may bereplaced/substituted with at least one of the PSCCH, the first SCI,and/or the second SCI. Additionally/alternatively, for example, sincethe transmitting UE may transmit the second SCI to the receiving UE onthe PSSCH, the PSSCH may be replaced/substituted with the second SCI.

Hereinafter, synchronization acquisition by an SL UE will be described.

In TDMA and FDMA systems, accurate time and frequency synchronization isessential. Inaccurate time and frequency synchronization may lead todegradation of system performance due to inter-symbol interference (ISI)and inter-carrier interference (ICI). The same is true for V2X. Fortime/frequency synchronization in V2X, a sidelink synchronization signal(SLSS) may be used in the PHY layer, and master informationblock-sidelink-V2X (MIB-SL-V2X) may be used in the RLC layer.

FIG. 14 illustrates a V2X synchronization source or reference to whichthe present disclosure is applicable.

Referring to FIG. 14, in V2X, a UE may be synchronized with a GNSSdirectly or indirectly through a UE (within or out of network coverage)directly synchronized with the GNSS. When the GNSS is configured as asynchronization source, the UE may calculate a direct subframe number(DFN) and a subframe number by using a coordinated universal time (UTC)and a (pre)determined DFN offset.

Alternatively, the UE may be synchronized with a BS directly or withanother UE which has been time/frequency synchronized with the BS. Forexample, the BS may be an eNB or a gNB. For example, when the UE is innetwork coverage, the UE may receive synchronization informationprovided by the BS and may be directly synchronized with the BS.Thereafter, the UE may provide synchronization information to anotherneighboring UE. When a BS timing is set as a synchronization reference,the UE may follow a cell associated with a corresponding frequency (whenwithin the cell coverage in the frequency), a primary cell, or a servingcell (when out of cell coverage in the frequency), for synchronizationand DL measurement.

The BS (e.g., serving cell) may provide a synchronization configurationfor a carrier used for V2X or sidelink communication. In this case, theUE may follow the synchronization configuration received from the BS.When the UE fails in detecting any cell in the carrier used for the V2Xor sidelink communication and receiving the synchronizationconfiguration from the serving cell, the UE may follow a predeterminedsynchronization configuration.

Alternatively, the UE may be synchronized with another UE which has notobtained synchronization information directly or indirectly from the BSor GNSS. A synchronization source and a preference may be preset for theUE. Alternatively, the synchronization source and the preference may beconfigured for the UE by a control message provided by the BS.

A sidelink synchronization source may be related to a synchronizationpriority. For example, the relationship between synchronization sourcesand synchronization priorities may be defined as shown in Tables 5 and6. Tables 5 and 6 are merely an example, and the relationship betweensynchronization sources and synchronization priorities may be defined invarious manners.

TABLE 5 BS-based synchronization GNSS-based (eNB/gNB-based Prioritysynchronization synchronization) P0 GNSS BS P1 All UEs directly All UEsdirectly synchronized with GNSS synchronized with BS P2 All UEsindirectly All UEs indirectly synchronized with GNSS synchronized withBS P3 All other UEs GNSS P4 N/A All UEs directly synchronized with GNSSP5 N/A All UEs indirectly synchronized with GNSS P6 N/A All other UEs

TABLE 6 GNSS-based eNB/gNB-based Priority synchronizationsynchronization P0 GNSS BS P1 All UEs directly All UEs directlysynchronized with GNSS synchronized with BS P2 All UEs indirectly AllUEs indirectly synchronized with GNSS synchronized with BS P3 BS GNSS P4All UEs directly All UEs directly synchronized with BS synchronized withGNSS P5 All UEs indirectly All UEs indirectly synchronized with BSsynchronized with GNSS P6 Remaining UE(s) with Remaining UE(s) with lowpriority low priority

In Table 5 or Table 6, P0 may denote the highest priority, and P6 maydenote the lowest priority. In Table 5 or Table 6, the BS may include atleast one of a gNB or an eNB.

Whether to use GNSS-based synchronization or BS-based synchronizationmay be (pre)determined. In a single-carrier operation, the UE may deriveits transmission timing from an available synchronization reference withthe highest priority.

Cooperative Sync Signal Transmission for Beam Sweep Acceleration

When a very high frequency such as mmWave is used, beamforming may begenerally used in order to overcome a pathloss. In order to usebeamforming, the best beam pair should be detected from among severalbeam pairs between a transmitter and a receiver. This operation may becalled beam acquisition or beam tracking from the receiver perspective.In particular, analog beamforming is used for mmWave. Accordingly, inthe operation of beam acquisition or beam tracking, a vehicle needs toperform beam sweeping of switching between beams in different directionsat different times, using an antenna array thereof. In this case, thetime for beam acquisition or beam tracking increases according to thenumber of times of beam switching. However, in vehicle-to-vehicle (V2V)communication, fast beam acquisition or beam tracking is requiredbecause safety is one of the main purposes of communication,communication may be performed while moving at a high speed. Inaddition, unlike point-to-point communication between a general UE and aBS, V2V communication generally involves communication with multiplevehicles. Therefore, it is necessary to reduce unnecessary operation asmuch as possible in beam sweeping to ensure fast beam acquisition orbeam tracking for multiple vehicles.

In Tx/Rx beam sweeping, each Tx unit (RF chain) independently transmitsa signal during N symbols (or blocks), and the Rx terminal sweeps the Rxbeam in every period. Accordingly, the time required for the receivingside to receive a synchronization signal (SS) for synchronization withthe transmitting side is the product of the Tx SS transmission time (N)and the number of Rx beams. However, such an SS reception time causes alarge overhead in a V2V communication environment with high mobility.

Proposed herein is a procedure and operation required for a UE and a BSto perform for fast beam acquisition and beam tracking when beam searchis performed for a nearby vehicle in mmWave-band V2V communication.First, proposed is a method for reducing Tx/Rx beam sweeping bydesignating nearby vehicles as a vehicle group and allowing the vehiclesin the group to cooperate with each other to transmit/receive beams indifferent directions at the same time. In addition, proposed is a methodfor reducing Tx/Rx beam sweeping and perform fast beam acquisition andbeam tracking using vehicle group information and zone information(location information received from a map and GPS that the vehicle hasor infrastructure (BS)).

FIG. 15 illustrates a relationship between a group and a division. FIG.16 illustrates parameters related to beam sweeping in a specific group.

Referring to FIG. 16, 2-beam operation at vehicle 0 (Veh 0) means thatVeh 0 includes two RF units or two panels.

Parameters necessary for beam sweeping on a group-by-group basis aredefined below.

The notation used in the present disclosure may be defined as follows.

-   -   N: A symbol (or block) length required to transmit an SS when        forming a Tx beam using one RF chain.    -   N_(Tx): The default number of Tx beam directions to transmit the        sync signal or sync signal block with one Tx unit (one beam at        each time)). This parameter may vary between vehicles.    -   N_(Rx): The default number of Rx beam directions to receive the        sync signal or sync signal block with one Rx unit (one beam at        each time)). This parameter may vary between vehicles.    -   Group (G_(n)): A group of vehicles with Tx/Rx units that        cooperatively transmit/receive beams to cover the entire        candidate beam directions around the group. A plurality of        vehicles may form a group, or one vehicle may be a group. A        vehicle may have one or more Tx/Rx units.    -   Division: A beam direction for the group to transmit or receive        SS (the number of divisions: M). Here, the division may        correspond to the beam direction.    -   M: The number of divisions in a group for Tx or Rx beam        sweeping. For Tx beam sweeping, M corresponds to N_(Tx) if there        is one vehicle in the group. For Rx beam sweeping, M corresponds        to N_(Rx) if there is one vehicle in the group.    -   T_(v): The number of unit symbols (or blocks) required when the        v-th group performs Tx/Rx beam sweeping in all directions,        wherein each symbol (or block) corresponds to one beam        direction. Alternatively, it is the number of beam switching        required for the v-th group to perform beam sweeping in all        directions (e.g., the number of SSBs for beam sweeping in the NR        system). The maximum value of T_(v) is N_(Tx) or N_(Rx).    -   C_(v), the group coefficient of the v-th group, corresponds to        the number of beams that may be formed simultaneously in the        v-th group. Here, C_(v) may be defined by Equation 1 below. In        the equation, M is less than or equal to T_(v)C_(v).

C _(v)=ceil(M/T _(v))  [Equation 1]

Alternatively, when one UE is present in one group, C_(v) may bedetermined by Equation 2 below.

C _(v)=ceil(N _(Tx) /T _(v)),N _(Tx) ≤T _(v) C _(v)or C _(v)=ceil(N_(Rx) /T _(v)),N _(Rx) ≤T _(v) C _(v)  [Equation 2]

-   -   Zone coefficient (D_(n)): the least value of C_(v) among the        values of C_(v) of the divisions of a zone.    -   Zone (Z_(n)): Physical or logical location information around a        vehicle to scan the surrounding beam.

Hereinafter, a specific method for performing beam sweeping on agroup-by-group basis will be described. First, vehicles in an adjacentarea may be grouped into one group. In transmitting a sync signal (SS),Tx/Rx units in the group may cooperatively transmit the SSssimultaneously by dividing a space. At least one vehicle or UE may beincluded in one group, and at least one Tx/Rx unit may be included ineach vehicle or UE. Here, the Tx/Rx unit represents an array antenna oran array antenna panel.

Since the vehicle or UE that initially enters a specific area is notconnected to a nearby vehicle, the number of vehicles or UEs in thegroup related to the initially entering vehicle or UE is one. Theinitially entering vehicle or UE may receive an SS transmitted by anearby vehicle and group while sweeping the Rx beam. The vehicle or UEthat has performed the initial entry may transmit a request signal (e.g.SS) to form a group (or to be included in a corresponding group) in adirection in which the received signal strength is strong among thereceived SSs. The request signal to form a group is repeatedlytransmitted such that the other vehicle or group may receive the signal.The vehicle and group that receives the request signal may transmit aresponse signal according to the request. Thereafter, the vehicle havingtransmitted the request and the vehicle or group having transmitted theresponse signal may perform a procedure for (re-)forming a group.

The above-described operation is summarized as follows.

1. A group is formed by Tx/Rx units independent of each other form, andthe Tx/Rx units in the group cooperatively perform beam sweeping duringSS transmission.

2. In forming a group, the group may be formed between vehicles withoutthe assistance from a BS, or may be formed with the assistance from theBS.

3. After the group is formed, divisions may be configured based on thelocations of the vehicles and the Tx/Rx units in the group, such thatbeams are transmitted in all directions (wherein different divisions maypartially overlap each other).

4. The number of divisions in a group, M, is less than or equal to thenumber of Tx/Rx units in the group, P.

5. When one vehicle is included in the v-th group, the group coefficient(C_(v)) of the v-th group is determined as ceil(N_(Tx)/T_(v)). Here,T_(v)C_(v) must be greater than or equal to N.

6. Vehicles in a group cooperate with each other to sweep Tx/Rx beamswithin each allocated area to transmit/receive SSs.

7. When the Tx beam sweeping time of neighboring groups is known, theperiod for switching of the Rx beam may be determined.

8. By using zone information about the location of each group is used,beam sweeping may be performed more efficiently.

Proposed below is a method for performing fast beam acquisition and beamtracking by reducing the number of times of Tx/Rx beam sweeping moreefficiently additionally based on the zone information. Hereinafter, itis assumed that cooperation information includes zone information andgroup information.

FIG. 17 illustrates a relationship between zone information and a zonecoefficient according to an embodiment.

Referring to FIG. 17, the UE may acquire zone information from its ownmap information or infrastructure (BS). The vehicle transmits groupinformation and zone information thereon to a nearby vehicle or vehiclegroup. In this case, the information may be transmitted via theinfrastructure (BS) or through communication between vehicles fromdifferent groups. When the information is transmitted via theinfrastructure (BS), vehicles may transmit the group information thereon(such as Tx beam sweeping period) to the infrastructure (BS). Theinfrastructure (BS) updates the group information for each zone andtransmits the updated information to the vehicle. The Rx beam switchingperiod may be determined based on the received zone information andgroup information.

Alternatively, when the information is transmitted throughvehicle-to-vehicle communication, it is valid for vehicles performingthe communication between vehicles from different groups. Here, a groupis a set of vehicles performing cooperative beam sweeping, and does notnecessarily mean a set of all vehicles that communicate with each other.That is, the communication is not limited to communication betweenvehicles in a group. Thus, communication between vehicles from differentgroups is possible. When a vehicle in a group provides the zoneinformation and group information thereon to a vehicle in another group,the vehicle receiving the information may determine switches the Rx beamat a period for switching of the Rx beam, based on the collected zoneinformation and group information. Since the initially entering vehicleis not connected to a nearby vehicle, it cannot acquire groupinformation and zone information using V2V communication. Accordingly,the initially entering vehicle may acquire cooperation informationincluding the zone information and the group information from the BS.

Based on the group (G) information and zone information of FIG. 17,cooperation information including group information and zone informationfor beam sweeping as shown in Tables 7, 8, 9, 10, and 11 may bedelivered to a nearby vehicle and a vehicle performing beam search.First, a zone coefficient (D_(n)) is defined based on the zoneinformation and group information. The zone coefficient is the minimumvalue of C_(v) included in the zone. In FIG. 17, Zone 0 includes G0 andG3, and thus D0 thereof is min {C0, C3}. D2 is min{C1, C2} and D3 is C3.The zone coefficient of a zone that does not include any group isdefined as 0 or a specific value (default value) according to theoperation of the nearby vehicle and the vehicle performing beam search.

In searching for a nearby vehicle and a beam, when D_(n) of a zone isnot 0, the vehicle having acquired cooperation information as shown inTable 7, Table 8, and Table 9 below forms an Rx beam for a timecorresponding to Da toward the zone. When D_(n) is 0, it dos not formthe Rx beam toward the zone. The physical time required to maintain theRx beam is determined according to D_(n) and numerology P.

TABLE 7 Rx beam time information Zone0 P₀, D₀ Zone1 P₁, D₁ . . . ZoneA-1P_(A-1), D_(A-1)

TABLE 8 Rx beam time information Zone0 D₀ Zone1 D₁ . . . ZoneA-1 D_(A-1)Numerology P

TABLE 9 Rx beam time information Zone0 F₀ Zone1 F₁ . . . ZoneA-1 F_(A-1)

Table 7 shows a case where each group has different numerology. Thevehicle receiving D_(n) and numerology P included in the cooperationinformation calculates the physical time required to maintain the Rxbeam based on D_(n) and numerology P_(n). Referring to Table 8, P is arepresentative value of numerology corresponding to the maximum symbollength. Referring to Table 8, the vehicle receiving D_(n) and therepresentative value of numerology P calculates the physical timerequired to maintain the Rx beam based on D_(n) and numerology P. Thecase includes a case where groups have the same P.

Referring to Table 9, F_(n) included in the cooperation information is aparameter related to the physical time required to maintain the Rx beam.When information as shown in Table 9 is provided, the physical timeF_(n) required to maintain the Rx beam is directly notified to nearbyUEs.

Referring to Tables 10 and 11 below, without zone information, only theleast value among the values of the group coefficient excluding 0 isreported to the vehicle as the cooperation information. In this case,according to an embodiment, the signal overhead may be may be reducedcompared to the cooperation information in Tables 7 to 9. In searchingfor a nearby vehicle and a beam, a vehicle acquiring cooperationinformation corresponding to Tables 10 to 11 forms an Rx beam in one Rxbeam direction for a time corresponding to D_(min) if there is nospecial restriction on a specific Rx beam direction (e.g., a constrainton beam maintenance in the specific Rx beam direction).

TABLE 10 Rx beam time information Min Zone Coefficient D_(min) = min{D_(n) > 0} Numerology: P

TABLE 11 Rx beam time information Fmax

Referring to Table 10, P included in the cooperation information is arepresentative value of numerology corresponding to the maximum symbollength. Table 110 shows a case where each group has differentnumerology. The vehicle receiving D_(n) and the representative value ofnumerology P calculates the physical time required to maintain the Rxbeam based on D_(n) and numerology P.

Referring to Table 11, F_(max) is a parameter for the maximum value ofthe physical time for maintaining the Rx beam calculated based on D_(n)and numerology P. Alternatively, F_(max) as shown in Table 11 may beincluded in the cooperation information and directly delivered to nearbyvehicles or nearby groups.

FIG. 18 illustrates a beam sweep time required when cooperationinformation is not provided.

Referring to FIG. 18, one vehicle may consider 16 directions asdirections for Tx beam sweeping. In this case, since the cooperationinformation in FIG. 17 is not provided, the UE or the vehicle shouldperform beam sweeping in all directions.

FIG. 19 illustrates a beam sweeping time based on the cooperationinformation.

Referring to FIG. 19, one vehicle may consider 16 directions asdirections for beam sweeping for a Tx beam. Unlike in the case of FIG.18, the UE or vehicle does not need to perform beam sweeping in alldirections based on the provided cooperation information. As such, withbeam sweeping based on the cooperation information, the time requiredfor the UE or vehicle to perform beam sweeping may be significantlyreduced.

FIG. 20 illustrates a method for performing beam sweeping based on groupinformation and cooperation information.

Referring to FIG. 20, a UE or vehicle (hereinafter, UE) may transmit agroup join request signal to a nearby group to form a group (S901). Whenthe UE receives a response signal from the group that receives the groupjoin request signal, a procedure for joining the group may be performed.

Next, the UE may perform beam sweeping by cooperating with SStransmission within the group or reception of an SS from another groupon a group-by-group basis. The UE may perform beam sweeping throughgroup-by-group cooperation based on group information including regionallocation information about a plurality of regions allocated to therespective UEs related to the group received from the group (S903).Based on the received region allocation information, the UE maydetermine regions in which the UE is to perform beam sweeping among theplurality of regions related to the group. That is, the UE mayparticipate in cooperative beam sweeping for some of the plurality ofregions in which beam sweeping is to be performed in the group, based onthe region allocation information. For example, as shown in FIG. 16, thegroup may divide a surrounding area into a plurality of regions based onthe number of UEs included in the group, and/or the number of antennaarrays or antenna panels included in the group, and/or the number ofbeams that may be formed by the UEs included in the group. The groupinformation may be configured by a representative UE or vehicle of thegroup, or may be configured by the BS.

Here, within the region allocated by the group information, not only thedirection of the Tx beam but also the direction of the Rx beam forreceiving beams transmitted from another group may be determined. Thatis, the UE may determine or limit the direction of the Tx beam and thedirection of the Rx beam according to the group information.

Regarding the plurality of regions, at least one region corresponding toeach of the UEs may be preconfigured based on the location informationabout the UEs or the beam directions of the UEs. Specifically, referringto FIG. 19, a first group may include a first vehicle (Veh 0) and asecond vehicle (Veh 1). The first group may divide the surrounding areainto 11 regions based on the beam directions and the number of beams ofeach of the first and second vehicles, and location information aboutthe first and second vehicles. Here, the 11 regions may correspond to 11beam directions. In this case, according to the region allocationinformation (or group information), the first vehicle may be allocatedregions 0 to 5 as regions for performing group-by-group beam sweeping,and the second vehicle may be allocated regions 6 to 10, which are theremaining regions. Thereafter, the first vehicle may perform beamsweeping while sequentially switching between beam directions fromregion 0 to region 5. Similarly, the second vehicle may perform beamsweeping while sequentially switching between beam directions fromregion 6 to region 11. In this case, as shown in FIG. 19, the number ofdirections in which each vehicle is to form a beam and the number oftimes of beam searching may be reduced by cooperative group-by-groupbeam sweeping. With such group-by-group cooperative beam sweeping, theoverall beam sweeping time may be significantly reduced.

Alternatively, the UE included in the group may send the representativeUE (the representative UE in the group) or the BS a request for changeof the region allocated thereto based on a location relationship withother UEs in the group or a change in the location information about theUE. For example, when the horizontal or vertical position thereof withrespect to other UEs is changed, the UE may transmit, to the BS or therepresentative UE, a signal for request for change of the beam sweepingregion including information on the change of the horizontal or verticalpositional relationship. Thereafter, the UE may receive regionreallocation information about the changed region and perform beamsweeping on the reallocated region. Alternatively, the UE may transmit,to the BS or the representative UE, a signal requesting reduction of theregion in which the UE performs beam sweeping based on the batterycharge level of the UE being lowered below a specific level. Then, theBS or the representative UE may reallocate a region corresponding toeach of the UEs included in the group based on the reduction requestsignal. In this case, the UE may perform efficient power saving in anemergency by minimizing power consumption for beam sweeping according tothe reduction request signal.

Alternatively, the group information may further include information ona group coefficient related to the group. The group coefficient may becalculated by Equation 1 as described above. Here, the group coefficientcorresponds to the number of beams that may be simultaneously formed inthe group. As described above, the product of the group coefficient andTv may be greater than or equal to the value of N.

Alternatively, the UE included in the group may receive cooperationinformation from another group or transmit cooperation information toanother group. The UE may perform beam sweeping based on the cooperationinformation (or additionally considering the cooperation information)(S905). Alternatively, a plurality of groups may transmit groupinformation thereof to the BS, and the BS may transmit cooperationinformation configured based on the received group information to theplurality of groups. Here, the cooperation information may be used forbeam acquisition and beam tracking for other groups. That is, thecooperation information may be used to determine a direction of the Rxbeam for detecting a beam transmitted by another group or a beammaintaining time.

As shown in Tables 7 to 10, the cooperation information may includeinformation on a zone coefficient for each zone and/or information onnumerology for each zone. Specifically, a region within a predeterminedrange may be divided into a plurality of zones distinguished by latitudeand longitude. Here, zone indexes may be preset for the plurality ofzones. The BS or the reference group may determine or identify zones inwhich each of the groups is located based on the information of the zoneindexes. The BS or the reference group may determine the zonecoefficient for each of the plurality of zones based on the informationon the group coefficient delivered by each of the plurality of groups.Here, the zone coefficient may be determined as the least value amongthe group coefficients for a plurality of groups included in one zone.The BS or the reference group may deliver cooperation information on thezone coefficients preconfigured for the respective zones to neighboringgroups. The BS or the reference group may determine the zone coefficientto be 0 for a zone in which no group is present.

Upon receiving the cooperation information, the UE may determine adirection of an Rx beam to be formed in a region configured the UE basedon the cooperation information. The UE may determine the direction ofthe Rx beam based on the location of the zone and the coefficient of thezone included in the cooperation information. For example, the UE maydetermine a direction of the Rx beam so as to face a specific zone, andmay determine the number of Rx beams or a maintenance period of Rx beamsbased on the coefficient of the zone. The UE may not form an Rx beam inthe direction toward the zone in which the zone coefficient is 0.

Alternatively, the UE may determine the direction of the Rx beamconsidering the cooperation information and the group information at thesame time. For example, even when the zone coefficient for a specificzone is not 0, the UE may not form an Rx beam toward the specific zoneif the direction to the specific zone is not within the region allocatedby the group information.

Alternatively, the UE may calculate a physical maintenance time for thedirection of the Rx beam to be formed for the corresponding zone, basedon the zone coefficient and/or the information on the numerologyincluded in the cooperation information. Specifically, when the numberof directions of Tx beams for each zone is preset to 10 and the zonecoefficient for a specific zone is 2, the UE may calculate a maintenancetime for the one Rx beam direction, considering that Tx beams in twodirections are simultaneously transmitted in the zone. For example,according to a preset gap Dss between neighboring synchronizationsignals, the UE may predict that the Tx beam for all directions of thespecific group will be received within the time Dss*5, and determine themaintenance time for the Rx beam direction for the specific group asDss*5 (where 5 may be calculated by the number of Tx beams/zonecoefficients for all directions for a specific group). When the numberof transmitted Tx beams (or numerology) differs among zones, thecooperation information may include information on the numerologycorresponding to each zone.

Alternatively, the cooperation information may include information on aphysical maintenance time, a maintenance time for Rx beam directioncorresponding to each zone, and the UE may determine a maintenance timefor the Rx beam for a predetermined zone based on the cooperationinformation.

Communication System Example to which the Present Disclosure is Applied

Although not limited thereto, various descriptions, functions,procedures, proposals, methods, and/or operational flow charts of thepresent disclosure disclosed in this document can be applied to variousfields requiring wireless communication/connection (5G) between devices.

Hereinafter, it will be illustrated in more detail with reference to thedrawings. In the following drawings/description, the same referencenumerals may exemplify the same or corresponding hardware blocks,software blocks, or functional blocks, unless otherwise indicated.

FIG. 21 illustrates a communication system applied to the presentdisclosure.

Referring to FIG. 21, a communication system 1 applied to the presentdisclosure includes wireless devices, Base Stations (BSs), and anetwork. Herein, the wireless devices represent devices performingcommunication using Radio Access Technology (RAT) (e.g., 5G New RAT(NR)) or Long-Term Evolution (LTE)) and may be referred to ascommunication/radio/5G devices. The wireless devices may include,without being limited to, a robot 100 a, vehicles 100 b-1 and 100 b-2,an eXtended Reality (XR) device 100 c, a hand-held device 100 d, a homeappliance 100 e, an Internet of Things (IoT) device 100 f, and anArtificial Intelligence (AI) device/server 400. For example, thevehicles may include a vehicle having a wireless communication function,an autonomous driving vehicle, and a vehicle capable of performingcommunication between vehicles. Herein, the vehicles may include anUnmanned Aerial Vehicle (UAV) (e.g., a drone). The XR device may includean Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality (MR) deviceand may be implemented in the form of a Head-Mounted Device (HMD), aHead-Up Display (HUD) mounted in a vehicle, a television, a smartphone,a computer, a wearable device, a home appliance device, a digitalsignage, a vehicle, a robot, etc. The hand-held device may include asmartphone, a smartpad, a wearable device (e.g., a smartwatch or asmartglasses), and a computer (e.g., a notebook). The home appliance mayinclude a TV, a refrigerator, and a washing machine. The IoT device mayinclude a sensor and a smartmeter. For example, the BSs and the networkmay be implemented as wireless devices and a specific wireless device200 a may operate as a BS/network node with respect to other wirelessdevices.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g.,NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300, thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without passing through theBSs/network. For example, the vehicles 100 b-1 and 100 b-2 may performdirect communication (e.g. Vehicle-to-Vehicle(V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b, or 150 c may beestablished between the wireless devices 100 a to 100 f/BS 200, or BS200/BS 200. Herein, the wireless communication/connections may beestablished through various RATs (e.g., 5G NR) such as uplink/downlinkcommunication 150 a, sidelink communication 150 b (or, D2Dcommunication), or inter BS communication (e.g. relay, Integrated AccessBackhaul(IAB)). The wireless devices and the BSs/the wireless devicesmay transmit/receive radio signals to/from each other through thewireless communication/connections 150 a and 150 b. For example, thewireless communication/connections 150 a and 150 b may transmit/receivesignals through various physical channels. To this end, at least a partof various configuration information configuring processes, varioussignal processing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocating processes, for transmitting/receiving radio signals, may beperformed based on the various proposals of the present disclosure.

Examples of Wireless Devices to which the Present Disclosure is Applied

FIG. 22 illustrates a wireless device applicable to the presentdisclosure.

Referring to FIG. 22, a first wireless device 100 and a second wirelessdevice 200 may transmit radio signals through a variety of RATs (e.g.,LTE and NR). Herein, {the first wireless device 100 and the secondwireless device 200} may correspond to {the wireless device 100 x andthe BS 200} and/or {the wireless device 100 x and the wireless device100 x} of FIG. 21.

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 102 may process informationwithin the memory(s) 104 to generate first information/signals and thentransmit radio signals including the first information/signals throughthe transceiver(s) 106. The processor(s) 102 may receive radio signalsincluding second information/signals through the transceiver 106 andthen store information acquired by processing the secondinformation/signals in the memory(s) 104. The memory(s) 104 may beconnected to the processor(s) 102 and may store a variety of informationrelated to operations of the processor(s) 102. For example, thememory(s) 104 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 102or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 102 and the memory(s) 104 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 106 may be connected to the processor(s) 102 andtransmit and/or receive radio signals through one or more antennas 108.Each of the transceiver(s) 106 may include a transmitter and/or areceiver. The transceiver(s) 106 may be interchangeably used with RadioFrequency (RF) unit(s). In the present disclosure, the wireless devicemay represent a communication modem/circuit/chip

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 202 may process informationwithin the memory(s) 204 to generate third information/signals and thentransmit radio signals including the third information/signals throughthe transceiver(s) 206. The processor(s) 202 may receive radio signalsincluding fourth information/signals through the transceiver(s) 106 andthen store information acquired by processing the fourthinformation/signals in the memory(s) 204. The memory(s) 204 may beconnected to the processor(s) 202 and may store a variety of informationrelated to operations of the processor(s) 202. For example, thememory(s) 204 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 202or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 202 and the memory(s) 204 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 206 may be connected to the processor(s) 202 andtransmit and/or receive radio signals through one or more antennas 208.Each of the transceiver(s) 206 may include a transmitter and/or areceiver. The transceiver(s) 206 may be interchangeably used with RFunit(s). In the present disclosure, the wireless device may represent acommunication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP,RRC, and SDAP). The one or more processors 102 and 202 may generate oneor more Protocol Data Units (PDUs) and/or one or more Service Data Unit(SDUs) according to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Theone or more processors 102 and 202 may generate messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document. The one or more processors 102 and 202 maygenerate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document and provide thegenerated signals to the one or more transceivers 106 and 206. The oneor more processors 102 and 202 may receive the signals (e.g., basebandsignals) from the one or more transceivers 106 and 206 and acquire thePDUs, SDUs, messages, control information, data, or informationaccording to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreApplication Specific Integrated Circuits (ASICs), one or more DigitalSignal Processors (DSPs), one or more Digital Signal Processing Devices(DSPDs), one or more Programmable Logic Devices (PLDs), or one or moreField Programmable Gate Arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument may be implemented using firmware or software and the firmwareor software may be configured to include the modules, procedures, orfunctions. Firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be included in the one or more processors102 and 202 or stored in the one or more memories 104 and 204 so as tobe driven by the one or more processors 102 and 202. The descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be implemented using firmware or softwarein the form of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured by Read-OnlyMemories (ROMs), Random Access Memories (RAMs), Electrically ErasableProgrammable Read-Only Memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, from one or moreother devices. For example, the one or more transceivers 106 and 206 maybe connected to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may perform control so that the one or more transceivers 106 and 206may transmit user data, control information, or radio signals to one ormore other devices. The one or more processors 102 and 202 may performcontrol so that the one or more transceivers 106 and 206 may receiveuser data, control information, or radio signals from one or more otherdevices. The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or more transceivers106 and 206 may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, through the one ormore antennas 108 and 208. In this document, the one or more antennasmay be a plurality of physical antennas or a plurality of logicalantennas (e.g., antenna ports). The one or more transceivers 106 and 206may convert received radio signals/channels etc. from RF band signalsinto baseband signals in order to process received user data, controlinformation, radio signals/channels, etc. using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206 mayconvert the user data, control information, radio signals/channels, etc.processed using the one or more processors 102 and 202 from the baseband signals into the RF band signals. To this end, the one or moretransceivers 106 and 206 may include (analog) oscillators and/orfilters.

Examples of Wireless Devices to which the Present Disclosure is Applied

FIG. 23 illustrates another example of a wireless device applied to thepresent disclosure. The wireless device may be implemented in variousforms according to a use-case/service (refer to FIG. 21)

Referring to FIG. 23, wireless devices 100 and 200 may correspond to thewireless devices 100 and 200 of FIG. 22 and may be configured by variouselements, components, units/portions, and/or modules. For example, eachof the wireless devices 100 and 200 may include a communication unit110, a control unit 120, a memory unit 130, and additional components140. The communication unit may include a communication circuit 112 andtransceiver(s) 114. For example, the communication circuit 112 mayinclude the one or more processors 102 and 202 and/or the one or morememories 104 and 204 of FIG. 22. For example, the transceiver(s) 114 mayinclude the one or more transceivers 106 and 206 and/or the one or moreantennas 108 and 208 of FIG. 22. The control unit 120 is electricallyconnected to the communication unit 110, the memory 130, and theadditional components 140 and controls overall operation of the wirelessdevices. For example, the control unit 120 may control anelectric/mechanical operation of the wireless device based onprograms/code/commands/information stored in the memory unit 130. Thecontrol unit 120 may transmit the information stored in the memory unit130 to the exterior (e.g., other communication devices) via thecommunication unit 110 through a wireless/wired interface or store, inthe memory unit 130, information received through the wireless/wiredinterface from the exterior (e.g., other communication devices) via thecommunication unit 110.

The additional components 140 may be variously configured according totypes of wireless devices. For example, the additional components 140may include at least one of a power unit/battery, input/output (I/O)unit, a driving unit, and a computing unit. The wireless device may beimplemented in the form of, without being limited to, the robot (100 aof FIG. 21), the vehicles (100 b-1 and 100 b-2 of FIG. 21), the XRdevice (100 c of FIG. 21), the hand-held device (100 d of FIG. 21), thehome appliance (100 e of FIG. 21), the IoT device (100 f of FIG. 21), adigital broadcast terminal, a hologram device, a public safety device,an MTC device, a medicine device, a fintech device (or a financedevice), a security device, a climate/environment device, the AIserver/device (400 of FIG. 21), the BSs (200 of FIG. 21), a networknode, etc. The wireless device may be used in a mobile or fixed placeaccording to a use-example/service.

In FIG. 23, the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200 maybe connected to each other through a wired interface or at least a partthereof may be wirelessly connected through the communication unit 110.For example, in each of the wireless devices 100 and 200, the controlunit 120 and the communication unit 110 may be connected by wire and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslyconnected through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured by a set of one or more processors. As an example, thecontrol unit 120 may be configured by a set of a communication controlprocessor, an application processor, an Electronic Control Unit (ECU), agraphical processing unit, and a memory control processor. As anotherexample, the memory 130 may be configured by a Random Access Memory(RAM), a Dynamic RAM (DRAM), a Read Only Memory (ROM)), a flash memory,a volatile memory, a non-volatile memory, and/or a combination thereof.

Hereinafter, an example of implementing FIG. 23 will be described indetail with reference to the drawings.

Examples of Mobile Devices to which the Present Disclosure is Applied

FIG. 24 illustrates a hand-held device applied to the presentdisclosure. The hand-held device may include a smartphone, a smartpad, awearable device (e.g., a smartwatch or a smartglasses), or a portablecomputer (e.g., a notebook). The hand-held device may be referred to asa mobile station (MS), a user terminal (UT), a Mobile Subscriber Station(MSS), a Subscriber Station (SS), an Advanced Mobile Station (AMS), or aWireless Terminal (WT).

Referring to FIG. 24, a hand-held device 100 may include an antenna unit108, a communication unit 110, a control unit 120, a memory unit 130, apower supply unit 140 a, an interface unit 140 b, and an I/O unit 140 c.The antenna unit 108 may be configured as a part of the communicationunit 110. Blocks 110 to 130/140 a to 140 c correspond to the blocks 110to 130/140 of FIG. 23, respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from other wireless devices or BSs. Thecontrol unit 120 may perform various operations by controllingconstituent elements of the hand-held device 100. The control unit 120may include an Application Processor (AP). The memory unit 130 may storedata/parameters/programs/code/commands needed to drive the hand-helddevice 100. The memory unit 130 may store input/output data/information.The power supply unit 140 a may supply power to the hand-held device 100and include a wired/wireless charging circuit, a battery, etc. Theinterface unit 140 b may support connection of the hand-held device 100to other external devices. The interface unit 140 b may include variousports (e.g., an audio I/O port and a video I/O port) for connection withexternal devices. The I/O unit 140 c may input or output videoinformation/signals, audio information/signals, data, and/or informationinput by a user. The I/O unit 140 c may include a camera, a microphone,a user input unit, a display unit 140 d, a speaker, and/or a hapticmodule.

As an example, in the case of data communication, the I/O unit 140 c mayacquire information/signals (e.g., touch, text, voice, images, or video)input by a user and the acquired information/signals may be stored inthe memory unit 130. The communication unit 110 may convert theinformation/signals stored in the memory into radio signals and transmitthe converted radio signals to other wireless devices directly or to aBS. The communication unit 110 may receive radio signals from otherwireless devices or the BS and then restore the received radio signalsinto original information/signals. The restored information/signals maybe stored in the memory unit 130 and may be output as various types(e.g., text, voice, images, video, or haptic) through the I/O unit 140c.

Examples of Vehicles or Autonomous Vehicles to which the PresentDisclosure is Applied

FIG. 25 illustrates a vehicle or an autonomous driving vehicle appliedto the present disclosure. The vehicle or autonomous driving vehicle maybe implemented by a mobile robot, a car, a train, a manned/unmannedAerial Vehicle (AV), a ship, etc.

Referring to FIG. 25, a vehicle or autonomous driving vehicle 100 mayinclude an antenna unit 108, a communication unit 110, a control unit120, a driving unit 140 a, a power supply unit 140 b, a sensor unit 140c, and an autonomous driving unit 140 d. The antenna unit 108 may beconfigured as a part of the communication unit 110. The blocks110/130/140 a to 140 d correspond to the blocks 110/130/140 of FIG. 23,respectively

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous driving vehicle 100. The control unit 120 mayinclude an Electronic Control Unit (ECU). Also, the driving unit 140 amay cause the vehicle or the autonomous driving vehicle 100 to drive ona road. The driving unit 140 a may include an engine, a motor, apowertrain, a wheel, a brake, a steering device, etc. The power supplyunit 140 b may supply power to the vehicle or the autonomous drivingvehicle 100 and include a wired/wireless charging circuit, a battery,etc. The sensor unit 140 c may acquire a vehicle state, ambientenvironment information, user information, etc. The sensor unit 140 cmay include an Inertial Measurement Unit (IMU) sensor, a collisionsensor, a wheel sensor, a speed sensor, a slope sensor, a weight sensor,a heading sensor, a position module, a vehicle forward/backward sensor,a battery sensor, a fuel sensor, a tire sensor, a steering sensor, atemperature sensor, a humidity sensor, an ultrasonic sensor, anillumination sensor, a pedal position sensor, etc. The autonomousdriving unit 140 d may implement technology for maintaining a lane onwhich a vehicle is driving, technology for automatically adjustingspeed, such as adaptive cruise control, technology for autonomouslydriving along a determined path, technology for driving by automaticallysetting a path if a destination is set, and the like

For example, the communication unit 110 may receive map data, trafficinformation data, etc. from an external server. The autonomous drivingunit 140 d may generate an autonomous driving path and a driving planfrom the acquired data. The control unit 120 may control the drivingunit 140 a such that the vehicle or the autonomous driving vehicle 100may move along the autonomous driving path according to the driving plan(e.g., speed/direction control). In the middle of autonomous driving,the communication unit 110 may aperiodically/periodically acquire recenttraffic information data from the external server and acquiresurrounding traffic information data from neighboring vehicles. In themiddle of autonomous driving, the sensor unit 140 c may obtain a vehiclestate and/or surrounding environment information. The autonomous drivingunit 140 d may update the autonomous driving path and the driving planbased on the newly acquired data/information. The communication unit 110may transfer information about a vehicle position, the autonomousdriving path, and/or the driving plan to the external server. Theexternal server may predict traffic information data using AItechnology, etc., based on the information collected from vehicles orautonomous driving vehicles and provide the predicted trafficinformation data to the vehicles or the autonomous driving vehicles.

The embodiments described above are those in which components andfeatures of the present disclosure are combined in a predetermined form.Each component or feature should be considered optional unlessexplicitly stated otherwise. Each component or feature may beimplemented in a form that is not combined with other components orfeatures. In addition, it is also possible to constitute an embodimentof the present disclosure by combining some components and/or features.The order of operations described in the embodiments of the presentdisclosure may be changed. Some configurations or features of oneembodiment may be included in other embodiments, or may be replaced withcorresponding configurations or features of other embodiments. It isobvious that the embodiments may be configured by combining claims thatdo not have an explicit citation relationship in the claims or may beincluded as new claims by amendment after filing.

In this document, embodiments of the present disclosure have been mainlydescribed based on a signal transmission/reception relationship betweena terminal and a base station. Such a transmission/receptionrelationship is extended in the same/similar manner to signaltransmission/reception between a terminal and a relay or a base stationand a relay. A specific operation described as being performed by a basestation in this document may be performed by its upper node in somecases. That is, it is obvious that various operations performed forcommunication with a terminal in a network comprising a plurality ofnetwork nodes including a base station may be performed by the basestation or network nodes other than the base station. The base stationmay be replaced by terms such as a fixed station, a Node B, an eNode B(eNB), an access point, and the like. In addition, the terminal may bereplaced with terms such as User Equipment (UE), Mobile Station (MS),Mobile Subscriber Station (MSS).

In a hardware configuration, the embodiments of the present disclosuremay be achieved by one or more application specific integrated circuits(ASICs), digital signal processors (DSPs), digital signal processingdevices (DSPDs), programmable logic devices (PLDs), field programmablegate arrays (FPGAs), processors, controllers, microcontrollers,microprocessors, etc.

In a firmware or software configuration, a method according toembodiments of the present disclosure may be implemented in the form ofa module, a procedure, a function, etc. Software code may be stored in amemory unit and executed by a processor. The memory unit is located atthe interior or exterior of the processor and may transmit and receivedata to and from the processor via various known means

As described before, a detailed description has been given of preferredembodiments of the present disclosure so that those skilled in the artmay implement and perform the present disclosure. While reference hasbeen made above to the preferred embodiments of the present disclosure,those skilled in the art will understand that various modifications andalterations may be made to the present disclosure within the scope ofthe present disclosure. For example, those skilled in the art may usethe components described in the foregoing embodiments in combination.The above embodiments are therefore to be construed in all aspects asillustrative and not restrictive. The scope of the disclosure should bedetermined by the appended claims and their legal equivalents, not bythe above description, and all changes coming within the meaning andequivalency range of the appended claims are intended to be embracedtherein.

The above-described embodiments of the present disclosure are applicableto various mobile communication systems.

What is claimed is:
 1. A method for performing beam sweeping by a userequipment (UE) in a wireless communication system supporting sidelink,the method comprising: forming a first group for performing the beamsweeping; receiving group information related to the first group; andperforming the beam sweeping based on the group information, wherein thegroup information includes region allocation information on a pluralityof regions divided based on the number of beams formable by UEs includedin the first group, wherein the beam sweeping is performed only in afirst region preconfigured to correspond to the UE among the pluralityof regions.
 2. The method of claim 1, wherein the group informationfurther includes information on a group coefficient (G_(v)) related tothe first group, wherein the group coefficient is determined byceil(M/T_(v)), wherein M is the number of the plurality of regions, andT_(v) is the number of synchronization signal blocks (SSBs) needed forthe first group to perform the beam sweeping.
 3. The method of claim 2,wherein the group coefficient corresponds to the number of beamssimultaneously formable in the first group.
 4. The method of claim 2,wherein a product of the T_(v) and the group coefficient is greater thana length of a symbol required to transmit a synchronization signalthrough one beam.
 5. The method of claim 2, further comprising:receiving cooperation information including information on a pluralityof zones divided based on a latitude and a longitude and information ona zone coefficient for each of the plurality of zones, wherein the zonecoefficient is set to a least value of the group coefficient for each ofat least one group located in a corresponding one of the zones.
 6. Themethod of claim 5, wherein the cooperation information further includesinformation on a time for maintaining a reception beam for each of theplurality of zones.
 7. The method of claim 5, wherein a direction of thereception beam for the beam sweeping is determined based on thecooperation information.
 8. The method of claim 7, wherein the receptionbeam is not formed toward a zone having the zone coefficient equal to 0.9. The method of claim 7, wherein the direction of the reception beamfor the beam sweeping is determined based on the region allocationinformation and the cooperation information.
 10. The method of claim 7,wherein a time required to maintain the direction of the reception beamis determined based on the zone coefficient.
 11. The method of claim 1,wherein the first region is a region corresponding to locationinformation about the UE among the plurality of regions.
 12. The methodof claim 1, wherein a transmission beam for the beam sweeping is formedonly in a direction of a beam directed toward the first region.
 13. Anapparatus for performing beam sweeping in a wireless communicationsystem supporting sidelink, the apparatus comprising: a radio frequency(RF) transceiver; and a processor connected to the RF transceiver,wherein the processor controls the transceiver to: form a first groupfor performing the beam sweeping; receive group information related tothe first group; and perform the beam sweeping based on the groupinformation, wherein the group information includes region allocationinformation on a plurality of regions divided based on the number ofbeams formable by UEs included in the first group, wherein the beamsweeping is performed only in a first region preconfigured to correspondto the UE among the plurality of regions.
 14. The apparatus of claim 13,wherein the processor controls a driving mode for the apparatus based onthe group information.